Camera shutter and viewfinder control apparatus

ABSTRACT

A shutter device for a still video camera comprises first and second shutter blades, a latch member and an unlatch member. The latch member latches the first blade at its moved position where an image pickup element is exposed to an image light. The first blade is kept latched for a preparatory exposure to correct a set exposure value on the basis of the output of the pickup element or for picking up a motion picture. The unlatch member releases the latching of the first blade. In one embodiment, the unlatch member is provided on the second blade to unlatch the first blade when the second blade is moved to terminate the exposure. In other embodiments, the unlatch member includes an electromagnet to unlatch the first blade. 
     A still video camera comprises a view finder mirror and a mirror operating mechanism. The mechanism includes a motor and is arranged to retract and return the mirror relative to an optical path by utilizing a normal and a reverse rotation of the motor, respectively. 
     In the disclosed embodiments, the camera further comprises a mechanism to maintain the mirror in the retracted condition and a shutter in the opened condition to operate in a motion video mode where an image pickup element is continuously exposed to an image light. The mechanism for setting in the motion video mode may be operable manually from the exterior of the camera or by connecting an external device to the camera.

This application is a continuation of application Ser. No. 945,948 filed12/24/86, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention in one aspect relates to a camera shutter control.In another aspect the present invention relates to a camera having asingle lens reflex view finder structure. More particularly, in thisaspect the present invention concerns a camera having viewfinder opticalmeans which is arranged to be retracted from an optical path at the timeof picture taking and then returned to an original position in theoptical path.

2. Description of the Related Art

Recently, there have been significant developments in connection withstill video cameras which use an image pickup element such as a CCD toconvert a light image into a corresponding electrical signal and torecord the signal magnetically on a medium such as a video floppy disc.

In a still video camera, an automatic exposure (AE) control system ofhigh precision is required in view of the narrowness of the dynamicrange of the image pickup element. Thus, though it could be possible tocontrol a stop value or a shutter speed based on an output of aphotocell such as a silicon photocell (SPC) for measuring the objectbrightness, like in a film camera, it is difficult to construct an AEcontrol system of high precision with that method due to the differencein the sensitivity and in the dynamic range between the image pickupelement and the photocell.

In view of the above, there has been provided an AE control in which theimage pickup element is first exposed to the image light for the purposeof determining the stop value or the shutter speed on the basis of theoutput of the photocell (a preparatory exposure). The stop value or theshutter speed is corrected based on the then obtained luminous output ofthe image pickup element to carry out the exposure of the pickup elementfor the image pickup (a true exposure). Thereafter the image pickupelement is again exposed to the image light for the purpose of takingthe picture.

FIG. 1 shows one example of such an AE control system. In the systemshown in FIG. 1, a light measuring circuit 101 includes a photocell(SPC) and produces an output signal representing an object brightness.An information input circuit 102 produces information signalsrepresenting a set shutter speed (i.e. exposure time) or a set stopvalue (i.e. aperture size) and a full open lens F Number. In operation,circuit 103 is connected to receive the output signals from the circuits101 and 102. A control circuit 104 is connected to receive the outputsignal from the operation circuit 103 and to control a diaphragm device105 and a shutter device 106 based thereon. An image pickup circuit 107includes an image pickup element (CCD) and produces an image signal anda luminous signal Y. A recording circuit 108 is connected to receive theoutput signal from the pickup circuit 107 and to record the signal on amedium such as a magnetic disc. The operation circuit 103 is connectedto receive the luminous signal Y produced by the pickup circuit 107 andto connect the shutter speed and/or the stop value based thereon.

The operation circuit 103 determines an appropriate stop value orshutter speed on the basis of the output signals of the light measuringcircuit 102 and of the information input circuit 102. Based on theoutput of the operation circuit 103, the control circuit 104 operates tostop down the diaphragm device 105 to the determined or set stop valueand to open the shutter device 106 a certain period of time to exposethe image pickup element (CCD) in the image pickup circuit 107 to theimage light 109 (preparatory exposure). Thus, the pickup circuit 107produces, together with the image signal, the luminous signal Yindicative of the object brightness. In response thereto, the operationcircuit 103 corrects the set or determined shutter speed and/or thedetermined or set stop value. Then, the control circuit 104 operates thediaphragm device 105 and the shutter device 106 based on the correctedoutput of the operation circuit 103 to expose the pickup element (CCD)in the pickup circuit 107 under the most proper condition (trueexposure). Thus, the most appropriate image signal is produced by thepickup circuit 107 and is recorded in the recording circuit 108.

In this system, the shutter device must be kept opened for a certainperiod of time for the preparatory exposure while it should be keptclosed in an unused condition of the camera in order to protect theimage pickup element from being damaged by the high intensity light etc.

However, if an electromagnetically driven focal plane type shutterdevice is used for the above mentioned shutter device, an electromagnetfor driving a first one of shutter blades must be kept energized duringthe preparatory exposure to maintain the shutter device opened and thiscauses much consumption of electrical power.

Moreover, if a motion picture is to be taken with the above mentionedstill video camera like a normal video camera, the shutter device shouldbe kept opened for a whole period of the motion picture taking and thiscauses much more consumption of electrical power.

As is well known in the art, a single lens reflex type camera must havea mechanism for retracting a viewfinder mirror from an optical path atthe time of picture taking and for thereafter returning the mirror toits original position in the optical path. Generally, such mechanismincludes a spring as a driving source for quick movement of the mirror.

One well known film camera incorporates a manual or built in motor typeautomatic wind up mechanism; and the charging of the spring for mirrorretraction is performed together with the film wind up by the wind upmechanism. Also, the releasing of a clutch for mirror return and thelatching of the wind up mechanism are performed by the operation of ashutter.

However, in the case of a still video camera using a video floppy disc,the film wind up mechanism may be of no use and therefore it is notpossible to charge the spring for mirror return by the film wind upmechanism.

Moreover, in the case of a still video camera, a very small and hencelightly operative shutter can be used because the picture size of thestill video camera is about one fourth of that of a 35 mm film camera.Therefore, it may be very difficult to release the clutch for mirrorreturn by the operation of such a small and lightly operative shutter.

Furthermore, it is not advisable to prepare an electro-magnet solely forthe releasing of the clutch for mirror return.

Other than the above, it would be very convenient to take with the abovementioned still video camera, a motion picture like in a normal videocamera, as well as a still picture. In this case, it would also beconvenient to use an EVF (Electronic viewfinder) to monitor the imagesignal. Furthermore, it would be highly convenient if a VCR (VideoCassette Recorder) could be connected to the still video camera torecord the picked up motion picture.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided acamera which comprises first and second shutter members, latch means andunlatch means. The first shutter member is movable between a restposition where it closes an aperture and a moved position where it opensthe aperture. The second shutter member is also movable between a restposition where it opens the aperture and a moved position where itcloses the aperture. The latch means latches the first shutter member atits moved position. The unlatch means is responsive to movement of thesecond shutter member to its moved position to release the latch means.

The camera may further comprise detection means and shutter controlmeans. The detection means detects a scene brightness when the apertureis opened by the movement of the first shutter member to its movedposition. The shutter control means causes the second and the firstshutter member to be returned, in the named order, from their respectivemoved to their respective rest positions with a time delay controlled onthe basis of the scene brightness detected by the detection means,therebetween. The shutter control means may be further arranged to causethe first and second shutter members to be moved, in the named order,from their respective rest positions to their respective moved positionswith a predetermined time delay therebetween.

The shutter control means may include first and second electromagneticmeans for moving the first and second shutter members, respectively, andcircuit means for controlling the first and second electromagneticmeans.

The camera may further comprise first and second urging members forurging the first and second shutter members toward their respective restpositions, respectively, and first and second stopper members forstopping the first and second shutter members at their respective restpositions, respectively. In this case, the first and secondelectromagnetic means are arranged to move the first and second shuttermembers to their respective moved positions and to hold the thereagainst the first and second urging members, respectively.

When the camera comprises a viewfinder mirror and means for moving themirror between a viewing position in an optical path and a retractedposition out of the optical path, the latch means may be arranged to beresponsive to the moving means to latch the first shutter member at itsmoved position when the mirror is moved to the retracted position by themoving means. Alternatively, when the camera comprises a diaphragmdevice and means for stopping down the diaphragm device, the latch meansmay be arranged to be responsive to the stop down means to latch thefirst shutter member at its moved position when the stop down meansstops down the diaphragm device. The camera may further comprise meansfor operating the latch means after the first shutter member has beenmoved to its moved position.

According to another aspect of the present invention, there is provideda camera which comprises a first and a second shutter member, latchmeans and unlatch means. The first shutter member is movable between arest position where it closes an aperture and a moved position where itopens the aperture. The second shutter member is also movable between arest position where it opens the aperture and a moved position where itcloses the aperture. The latch means latches the first shutter member atits moved position. The unlatch means includes an electromagnet torelease the latching of the first shutter member by the latch means.

The camera of this embodiment may further comprise unlatch control meansfor causing the unlatch means to release the latching of the firstshutter member by the latch means when the second shutter member ismoved to its moved position. The unlatch control means is connected toenergize the electromagnet.

According to a further aspect of the present invention, there isprovided a camera which comprises first and second shutter members,latch means, trigger means and unlatch means. The first shutter memberis movable between a rest position where it closes an aperture and amoved position where it opens the aperture. The second shutter member isalso movable between a rest position, where it opens the aperture, and amoved position where it closes the aperture. The latch means is providedfor latching the first shutter member at its moved position. The triggermeans includes an electromagnet to cause the latch means to latch thefirst shutter member. The unlatch means is responsive to the secondshutter member to release the latching of the first shutter member bythe latch means when the second shutter member is moved to its movedposition.

The camera of this embodiment may further comprise trigger control meansfor operating the trigger means after the first shutter member has beenmoved to its moved position. The trigger control means is connected tothe electromagnet. Other than the above, the same embodiment structuresas those in the first and the second aspect can be applied unless theyare inconsistent.

Thus, it becomes possible to greatly lessen the consumption of theelectrical power which is necessary to keep the electromagnetic driveshutter opened for a certain period of time.

According to a further aspect of the present invention, there isprovided a camera which comprises viewfinder optical means, prime movermeans, a retracting mechanism, latch means, unlatch means, and a resetmechanism. The optical means is supported movably between a firstposition in an optical path and a second position out of the opticalpath. The prime mover means has an output member which is alternativelymovable in first and second directions. The retracting mechanism movesthe optical means from the first to the second position. The latch meanslatches the retracting mechanism. The unlatch means is also responsiveto the movement of the output member of the prime mover means in thefirst direction to release the latching of the retracting mechanism bythe latch means to thereby enable the retracting means to move theoptical means from the first to the second position. The reset mechanismis responsive to the movement of the output member of the prime movermeans in the second direction to reset the optical means at the firstposition and the retracting mechanism at a condition operative to movethe optical means from the first to the second position.

The camera of this embodiment may include energy storing means and maybe arranged to operate by energy stored in the storing means. Thestoring means may be arranged to store energy when the retractingmechanism is reset by the reset mechanism. The latch means may bearranged to latch the retracting mechanism with the storing meansstoring energy. The storing means may include a spring. The retractingmeans may also include releasable clutch means and the reset means mayinclude urging means and release means. The urging means urges theoptical means toward the first position. The release means is responsiveto the movement of the output member of the prime mover means in thesecond direction to disconnect the clutch means to thereby enable theurging means to return the optical means to the first position. Theurging means may include a spring. The reset mechanism may furtherinclude drive means which is responsive to the movement of the outputmember of the prime mover means in the second direction to drive theretracting mechanism to reset the same. The clutch means may be arrangedto be connected with the optical means at the time of resetting of theretracting mechanism by the drive means. The release means may bearranged to operate in advance to the drive means by the movement of theoutput member of the prime mover means. The prime mover means mayinclude an electrical motor having an output shaft rotatable in a normaland a reverse direction. The view finder optical means may include amirror member supported moveably between the first and the secondposition. The optical means may be supported to be laterally swingablerelative to the optical path. The camera may further comprise imagepickup means for producing an electrical image signal in response to areceived light image. The pickup means may be arranged to receive thelight image along the optical path when the optical means is moved tothe second position by the retracting mechanism. The camera may furthercomprise recording means for recording the image signal produced by thepickup means.

According to another aspect of the present invention, there is provideda camera which comprises image pickup means, viewfinder optical means,shutter means, first means, second means, and third means. The imagepickup means produces an electrical image signal in response to imagelight passing along an optical path. The viewfinder optical means ismovable into and from the optical path. The shutter means exposes thepickup means to the image light. The first means temporarily retractsthe optical means from the optical path. The second means opens theshutter means for a controlled period of time in synchronism with theretraction of the optical means by the first means. The third meansmaintains the optical means in the retracted condition and the shuttermeans in the opened condition.

In the camera of this embodiment the third means may include manuallyoperable means for retracting the optical means from the optical pathand for opening the shutter means, and releasable lock means for lockingthe operable means in an operated condition. The first means may includeretracting means, charging means and motor means. The retracting meansis driven by charged energy to retract the optical means from theoptical path. The charging means charges the retracting means with thepower. The motor means is coupled to drive the charging means. The firstmeans may further include returning means responsive to the motor meansto return the optical means to an original position in the optical path.The first means may futher include latch means for latching theretracting means in the charged condition and release means forreleasing the latching of the retracting means by the latch means. Therelease means may be arranged to respond to the motor means to releasethe latching. The motor means may have an output member atlernativelyrotatable in first and second directions. The release means and thecharging means may be responsive to the rotation of the output member inthe first and second directions, respectively. Also, the release meansmay include electromagnet means to release the latching. In this case,the camera may further comprise manually operable trigger means forenergizing the electromagnet means to release the latching.

The camera may further comprise recording means for recording apredetermined image signal produced by the pickup means. The recordingmeans may include a magnetic disc recording device.

In another embodiment, the camera may further comprise socket means forenabling an external device to be connected to receive the image signalproduced by the image pickup means. In this case the third means mayinclude detection means for detecting the connection of the externaldevice to the socket means and retracting means responsive to thedetection means to retract the optical means from the optical path whenthe external device is connected to the socket means. The camera mayfurther comprise manually operable trigger means in which the thirdmeans may further include control means responsive to the detectionmeans and to the trigger means for maintaining the shutter means in theopened condition so long as the trigger means is operated when thedetection means detects the connection of the external device to thesocket means.

According to yet another aspect of the present invention, there isprovided a camera which comprises image pickup means, view finderoptical means, shutter means, socket means, detection means, firstmeans, and second means. The image pickup means produces an electricalimage signal in response to an image light coming along an optical path.The viewfinder optical means is movable into and from the optical path.The shutter means exposes the pickup means to the image light. Thesocket means enables an external device to be connected to receive theimage signal produced by the pickup means. The detection means detectsthe connection of the external device to the socket means. The firstmeans is responsive to the detection means to retract the optical meansfrom the optical path. The second means is responsive to the detectionmeans to open the shutter means.

The camera of this embodiment may further comprise manually operabletrigger means, in which the second means is further responsive to thetrigger means to maintain the shutter means in the opened condition whenthe trigger means is operated while detection means detects theconnection of the external device to the socket means. The camera mayfurther comprise recording means for recording a predetermined imagesignal produced by the pickup means. The recording means may include amagnetic disc recording device.

Thus, by the present invention, the retraction and the resetting of theviewfinder optical means relative to the optical path can be performedwith utilizing the movement of the output member of the prime movermeans in the first and the second direction, respectively; andtherefore, the mechanism for operating the optical means, and hence thecamera mechanism, can be made simple and compact and reliable operationof the optical means can be assured.

In addition, with the present invention, it becomes possible to utilizethe still video type camera as an usual motion video camera by adding asimple mechanical structure.

Furthermore, the present invention makes it possible to set the stillvideo type camera in a motion video mode by a simple operation ofconnecting an external device to the socket means.

These and other aspects, features and advantages of the presentinvention will become clear from the following detailed explanation ofthe preferred embodiments referring to the accompanied drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an electrical circuit system of a still video camera;

FIGS. 2A and 2B show a camera exposure mechanism of a first embodimentof the present invention in a rest condition and in a preparatoryexposure condition, respectively;

FIG. 3 is a block diagram of an electrical circuit system used with thecamera exposure mechanism of FIGS. 2A and 2B;

FIGS. 4A and 4B are flow control program diagrams showing control flowsperformed by the control circuit of FIG. 3 in a still video and in amotion video mode, respectively;

FIG. 5 shows a modification of the camera exposure mechanism of FIGS. 2Aand 2B;

FIGS. 6A and 6B show a camera exposure mechanism of a second embodimentof the present invention in a rest condition and in a preparatoryexposure condition, respectively;

FIG. 7 is a block diagram of an electrical circuit system used with thecamera exposure mechanism of FIGS. 6A and 6B;

FIGS. 8A and 8B are flow control program diagrams showing control flowsperformed by the control circuit of FIG. 7 in a still video and in amotion video mode, respectively;

FIG. 9 shows a modification of the camera exposure mechanism of theFIGS. 6A and 6B;

FIGS. 10A and 10B show a camera exposure mechanism of a third embodimentof the present invention in a rest condition and in a preparatoryexposure condition, respectively;

FIGS. 11A and 11B show a camera exposure mechanism of a fourthembodiment of the present invention in a rest condition and in apreparatory exposure condition, respectively;

FIG. 12 is a block diagram of an electrical circuit system used with thecamera exposure mechanism of FIGS. 11A and 11B; and

FIGS. 13A and 13B are flow control program diagrams showing controlflows performed by a control circuit of FIG. 12 in a still video and ina motion video mode, respectively.

FIG. 14 shows a camera exposure mechanism of a fifth embodiment of thepresent invention;

FIG. 15 shows an electrical circuit system used in the fifth embodiment;

FIG. 16 is a flow control program diagram which shows a control flowperformed by a control circuit in FIG. 15;

FIG. 17 shows the timing relationship of operation of the elements inFIG. 15;

FIG. 18 shows a camera exposure mechanism of a sixth embodiment of thepresent invention;

FIG. 19 shows a part of the mechanism shown in FIG. 18 at the time ofsetting in a motion video mode;

FIG. 20 shows an electrical circuit system of the sixth embodiment;

FIG. 21 shows a control flow performed by the control circuit of FIG.20;

FIG. 22 shows a camera exposure mechanism of a seventh embodiment of thepresent invention;

FIG. 23 shows a part of a camera housing of the seventh embodiment;

FIGS. 24A and 24B show a part of a charge mechanism in FIG. 22 indifferent operative conditions, respectively;

FIG. 25 shows an electrical circuit system of the seventh embodiment;and

FIG. 26 shows a control flow performed by a control circuit in FIG. 25.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of the present invention will be explained hereinbelow with reference to FIGS. 2A to 4B.

In the camera mechanism shown in FIGS. 2A and 2B, there are provided apair of shutter blades 1 and 2. These shutter blades 1 and 2 arepivotally mounted at a common axis 3 and are respectively urged bysprings 4 and 5 in a clockwise direction. Stopper pins 6 and 7 arerespectively provided for the shutter blades 1 and 2 to limit theirclockwise movement. The blades 1 and 2 are provided with pins 8 and 9mounted thereon, respectively. The first shutter blade 1, when it isrotated in the clockwise direction by the spring 4 until it strikes onthe stopper pin 6, closes a picture taking aperture 10; and when it isrotated in the counterclockwise direction against the spring 4, it opensthe aperture 10. The second shutter blade 2, when it is rotated in theclockwise direction by the spring 5 until it is restricted by thestopper pin 7, opens the aperture 10; and when it is rotated in thecounterclockwise direction against the spring 5, it closes the aperture10.

A shutter blade latch member 11 is pivotally mounted at an axis 12 andis urged by a spring 13 in a clockwise direction so that its arm part11b strikes on an arm part 14b of a drive member 14. The latch member 11is also provided with an arm part 11a to latch the first shutter blade 1at its pin 8 after the first shutter blade has been rotated in thecounterclockwise direction to open the aperture 10.

The drive member 14 is pivotally mounted at an axis 15 and is urged by aspring 16 in a counterclockwise direction so that its arm part 14cstrikes on a stopper pin 18. The drive member 14 is provided with threearm parts 14a, 14b and 14c; and the arm part 14c is provided with a pin17 mounted thereon.

A trigger member 19 is pivotally mounted at an axis 20 and is urged by aspring 21 to be hauled relative to the drive member 14 so that its armpart 19b strikes the pin 17 on the arm part 14c of the drive member 14.The trigger member 19 is provided with two arm parts 19a and 19b.

A lock member 22 is pivotally mounted at an axis 23 and is urged by aspring 24 in a clockwise direction. The lock member 22 is provided withtwo arm parts 22a and 22b. The arm part 22a is engageable with the pin 9on the second blade 2; and the arm part 22b is provided with a step part22c which is engageable with the tip of the arm part 14a of the drivemember 14.

A viewfinder mirror operating lever 25 is pivotally mounted at an axis26 and is urged by a spring 28 in a counterclockwise direction so thatit strikes on a stopper pin 29. The operating lever 25 is provided witha bent up part 25a and a tail part 25b. A pin 27 is mounted on theoperating lever 25.

A viewfinder mirror supporting lever 20 is pivotally mounted at an axis31 and supports a view finder mirror 32 at an inclined end part 30a sothat the mirror 32 is held in a predetermined inclined condition withrespect to a picture taking optical axis O. The supporting lever 30 hasa fork part 30b at its lower end which engages with the pin 27 on theoperating lever 25. The mirror 32 is held at a predetermined viewingposition in the optical path when the operating lever 25 is pivoted bythe spring 28 in the counterclockwise direction until it is restrictedby the stopper pin 29.

A diaphragm stop down lever 33 is arranged to be pushed by the bent uppart 25a of the mirror operating lever 25 to stop down a diaphragmdevice 34 having a known construction.

A link lever 35 is pivotally mounted on an axis 36 and is urged by aspring 37 in a counterclockwise direction. The link lever 35 is engagedwith the arm part 19a of the trigger member 19 and with the arm part 25bof the mirror operating lever 25 at its fore and tail end parts 35a and35b respectively.

Next, in the block diagram of FIG. 3, a synchronization signalgeneration circuit 202 (SSG hereinafter) is provided for generatingsynchronization signals. A drive circuit 203 is connected to drive animage pickup element 213 in response to the synchronization signalsupplied by the SSG circuit 202. The image pickup element 213 isarranged to receive image light through the camera aperture when themirror 32 (FIGS. 2A and 2B) is retracted from the optical path and theshutter is opened. A signal processing circuit 204, of a knownconstruction, is connected to receive and process the output signal ofthe image pickup element 213. A video floppy disc recording device 219of known construction is connected to receive and record the outputsignal of the processing circuit 204. An external output terminal 220 isalso connected to the output of the signal processing circuit 204.

A shutter speed setting circuit 205 is provided for setting a desiredshutter speed. A shutter control circuit 206 of a known construction isconnected to control the deenergization of electromagnets 217 and 218 inresponse to the output signal of the shutter speed setting circuit 205and the synchronization signal supplied from the SSG 202. Energizationcircuits 207 and 208 are respectively arranged to energize theelectromagnets 217 and 218 in response to the control signal suppliedfrom a control circuit 201 and deenergize the electromagnets 217 and 218in response to the control signal supplied from the shutter controlcircuit 206. The electromagnets 217 and 218 are arranged to move theshutter blades 1 and 2 (FIGS. 2A and 2B) against the springs 4 and 5,respectively when they are energized by the energization circuits 207and 208, respectively

A correction circuit 209 is connected to supply a shutter speedcorrection signal to the shutter speed setting circuit 205 based on aluminous signal Y supplied by the signal processing circuit 204. A stopvalve determination circuit 210 of known construction is connected toreceive a shutter speed signal Tv supplied from the shutter speedsetting circuit 205 and an object brightness signal Bv supplied by anobject brightness measuring element (photocell) 211. The measuringelement 211 may be positioned to receive object light through thediaphragm device 34 (FIGS. 2A and 2B) but not through the view findermirror 32. A diaphragm control mechanism 212 is connected to control thediaphragm device 34 in response to a stop value signal Av supplied bythe determination circuit 210.

The control circuit 201 is programmed to control the entire circuitsystem based on the conditions of switches 214, 215 and 216. The firstand second trigger switches 214 and 215 are respectively of normallyopen type and are arranged to be closed by a first and a second step ofthe depression of a trigger button 221, respectively. The mode selectswitch 216 is arranged to be manually operable to designate a stillvideo mode and a motion video mode by its opened and closed condition,respectively. The control circuit 201, which may comprise a microcomputer, has a control function shown by the flow charts of FIGS. 4Aand 4B.

Next, the operation of this embodiment will be explained with referenceto FIGS. 2A to 4B.

Operation in the still video mode will be explained first. The controlcircuit 201 operates the system in the still video mode when the modeselect switch 216 is opened (i.e. moved to the S terminal) and thecontrol function of the control circuit 201 is in the still video modeas shown in FIG. 4A.

In the condition shown in FIG. 2A, the control circuit 201 checks thefirst trigger switch 214 to ascertain whether it is closed by thedepression of the trigger button 221 to the extent of the first step(step S01 in FIG. 4A). If the switch 214 is found to be closed, thecontrol circuit 201 causes the circuits 202, 203, 204, 205 and 210 tooperate (step S02 in FIG. 4A). Thus, the SSG circuit 202 begins togenerate the synchronization signals and the drive circuit 203 alsobegins to drive the pickup element 213 based on the suppliedsynchronization signals. The output signal of the pickup element 213 isprocessed in the processing circuit 204 based on the synchronizationsignals supplied from the SSG circuit 202. On the other hand, the stopvalve determination circuit 210 determines the appropriate stop valuebased on the object brightness signal Bv supplied by the brightnessmeasuring element 211 and the shutter speed signal Tv supplied by theshutter speed setting circuit 205 in accordance with the preset shutterspeed set by the circuit 205, and produces the stop valve signal Avcorresponding to the determined stop value. In response to the stopvalue signal Av, the diaphragm control mechanism 212 controls a presetmeans of the diaphragm device 34 in accordance with the stop valverepresented by the signal Av. Thus, the stop value determined by thedetermination circuit 210 is preset to the diaphragm device 34.

The control circuit 201 waits for a time period of t₁ (step S03 in FIG.4A), which is sufficient for the completion of the above explained stopvalue determination and presetting operation; and then checks the secondtrigger switch 215 to ascertain whether it has been closed, by thedepression of the trigger button 221, to the extent of the second step(step S04 in FIG. 4A). If the switch 215 is found to be closed, thecontrol circuit 201 causes the stop value determination circuit 210 tohold the determined stop value (step S05 in FIG. 4A). Then the controlcircuit 201 commands the energization circuit 207 to energize theelectromagnet 217 for the first shutter blade 1 for a time period of t₂(step S06 in FIG. 4A). Thus, the first shutter blade 1 is rotated in thecounterclockwise direction against the spring 4 by the magnetic force ofthe electromagnet 217. Then, the mirror operating lever 25 is rotated inthe clockwise direction by a mirror retracting mechanism against thespring 28. Preferred mirror retracting mechanisms are shown in FIGS. 14,18, 19, 22, 24A and 24B. By this, the mirror supporting lever 30 isrotated in the counterclockwise direction to retract the viewfindermirror 32 from the optical path. At the same time, the stop down lever33 is pressed by the bent up part 25a of the operating lever 25 andstops down the diaphragm device 34 to the stop value determined by thestop value determination circuit 210 and preset by the central mechanism212. On the other hand, the link lever 35 is rotated in thecounterclockwise direction against the spring 37 by the clockwiserotation of the mirror operating lever 25; and causes the trigger member19 to rotate in the clockwise direction together with the drive member14 against the spring 16. Thus, the drive member 14 causes, through itsarm part 14b, the latch member 11 to rotate in the counterclockwisedirection against the spring 13 and to latch, through its arm art 11a,the first shutter blade 1 at the pin 8 thereon to hold the first shutterblade in its upper or opened condition. The drive member 14 is locked bythe step part 22c of the lock member 22 at its arm part 14a in therotated condition. The above explained operated condition is shown inFIG. 2B. Here, in this case, the fore end part 35a of the link lever 35is moved to the left side of the arm part 19a of the trigger member 19by overshooting the same as is shown by the dotted line 35a' in FIG. 2B.

When the time period of t₂ has elapsed, the control circuit 201 commandsthe energization circuit 207 to deenergize the electromagnet 217 (stepS07 in FIG. 4A). The time period of t₂ is selected to be sufficient forthe first shutter blade 1 to be rotated in the counterclockwisedirection and latched by the latch member 11. Thus, the aperture 10 iskept opened; and, in this condition, the control circuit 201 causes thecorrection circuit 209 to operate (step S08 in FIG. 4A). The correctioncircuit 209 detects the luminosity of the object scene based on theluminous signal Y supplied by the signal processing circuit 204 andproduces the shutter speed correction signal. In response to thiscorrection signal, the shutter speed setting circuit 205 corrects theset shutter speed and provides a corrected shutter speed signal to theshutter control circuit 206. After the step S08, the control circuit 201waits for a time period of t₃ (step S09 in FIG. 4A), which is sufficientfor the completion of the above explained shutter speed correctionoperation; and then causes the correction circuit 209 to hold thecorrection signal (step S10 in FIG. 4A).

The control circuit 201 thereupon commands the energization circuits 207and 208 to energize the electromagnets 217 and 218 (step S11 in FIG.4A). When the electromagnet 218 is energized, the second shutter blade 2is rotated in counterclockwise direction against the spring 5 by themagnetic force of the electromagnet 210 and closes the aperture 10. Atthis time, the pin 9 on the second shutter blade 2 presses the lockmember 22 at its arm part 22a and rotates the lock member 22 in thecounterclockwise direction against the spring 24. Thus, the lock member22 releases the locking of the drive member 14; and accordingly, thedrive member 14 is rotated in the counterclockwise direction by thespring 16 together with the trigger member 19 until the drive member 14is restricted by the stopper pin 18. By the counterclockwise rotation ofthe drive member 14, the latch member 11 is freed from pressing by thearm part 14b of the drive member 14 and rotates in the clockwisedirection by the spring 13 to release the latching of the first blade 1at its pin 8 through the arm part 11a thereof. The first blade 1 isthereupon kept at the counterclockwisely rotated condition by theelectromagnet 217.

The control circuit 201 then triggers the shutter control circuit 206(step S12 in FIG. 4A). When triggered, the shutter control circuit 206causes, in response to the vertical synchronization signal supplied bythe SSG circuit 202 right after the triggering, the energization circuit208 to deenergize the electromagnet 218. Then, after the time lagcorresponding to the shutter speed (exposure time) indicated by thecorrected shutter speed signal supplied by the shutter speed settingcircuit 205, the shutter control circuit 206 causes the energizationcircuit 207 to deenergize the electromagnet 217. Thus, the second andthe first shutter blades 2 and 1 are respectively rotated in theclockwise direction in the named order by the springs 5 and 4 at pointsin time separated by the above mentioned time lag. By this, the imagepickup element 213 is exposed to the object light for a time periodcorresponding to the time lag. The image signal generated in the pickupelement 213 in response to the light exposure is read out and suppliedto the recording device 219 after being processed by the signalprocessing circuit 204 during a field period immediately following thefield period during which the exposure of the pickup element 213 hasbeen made. Therefore, before the commencement of the reading out of theimage signal from the pickup element 213 after the exposure thereof, thecontrol circuit 201 triggers the recording device 219 (step S13 in FIG.4A); and by this, the recording device 219 records on the floppy discthe image signal supplied by the processing circuit 204 andcorresponding to one TV field, based on the synchronization signalsupplied by the SSG circuit 202.

After the completion of the exposure of the pickup element 213, theoperating lever 25 is freed from the latching by the mirror retractingmechanism, e.g. as shown in FIGS. 14, 18, 19, 22, 24A and 24B, andtherefore, the operating lever is rotated in the counterclockwisedirection by the spring 28 until it is restricted by the stopper pin 29.Thus, the supporting lever 30 is rotated in the counterclockwisedirection to return the view finder mirror 32 to the viewing position inthe optical path. At the same time, the link lever 35 follows theoperating lever 25 and is rotated in the clockwise direction by thespring 37, thus allowing the trigger member 19 to rotate in thecounterclockwise direction against the spring 21. As a result the foreend part 35a is returned to the right side of the arm part 19a of thetrigger member 19. Furthermore, the stop down lever 33 also follows theoperating lever 25 to return the diaphragm device 34 to the initialfully opened mechanism is returned to that condition. Thus, themechanism is returned to that condition shown in FIG. 2A. On the otherhand, on completion of signal recording by the recording device 219, thecontrol circuit 201 checks the switch 214 to ascertain whether it isopen (step S14 in FIG. 4A); and if the switch 214 is found to be open,the control circuit 201 deactivates the circuits 202, 203, 204, 205, 209and 210 (step S15 in FIG. 4A). This is the end of operation in the stillvideo mode.

The operation of the apparatus in the motion video mode will now beexplained. The control circuit 201 operates the system in the motionvideo mode when the mode select switch 216 is closed (i.e. moved to itsM terminal) and its control function in the motion video mode is shownin FIG. 4B.

In the condition shown in FIG. 2A, the control circuit 201 checks thefirst trigger switch 214 to ascertain whether it is closed (step S21 inFIG. 4B); and if it is found to be closed, the control circuit 201causes the shutter speed setting circuit 205 to set the shutter speed(exposure time) (Tv) at 1/60 sec. (step S22 in FIG. 4B) and thenactivates the circuits 202, 203, 204 and 210 (step S23 in FIG. 4B).After the step S23, the control circuit 201 checks the second triggerswitch 215 to ascertain whether it is closed (step S24 in FIG. 4B); andif it is found to be closed, the control circuit 201 commands theenergization circuit 207 to energize the electromagnet 217 for the timeperiod t₂ (step S25 in FIG. 4B). Thus, the first shutter blade 1 isrotated counter clockwise to open the aperture 10. Within the above timeperiod t₂, the mirror retracting mechanism operates on the operatinglever 25 to retract the mirror 32 from the optical path. By thisoperation, the first shutter blade 1 is latched at its aperture openingposition by the latch member 11 which, in turn, is locked by the lockmember 22 through the drive member 14, as is shown in FIG. 2B. Moreover,the diaphragm device 34 is stopped down by the stop down lever 33 to thestop value determined by the stop value determination circuit 210. Inthis case, the stop value determination circuit 210 determines orcontrols the stop value (Av) based on the brightness signal Bv suppliedby the measuring element 211 which receives the object light through thestopped down diaphragm device and the shutter speed signal Tvrepresenting an exposure time of 1/60 sec. which corresponds to the TVfield rate under NTSC system. (Therefore, under PAL system, an exposuretime of 1/50 sec. may be preferable.). In accordance with the stop valuesignal Av produced by the determination circuit 210, the diaphragmcontrol mechanism 212 controls the diaphragm device 34 to adjust thediaphragm aperture thereof. When the time period t₂ has elapsed, thecontrol circuit 201 commands the energization circuit 207 to deenergizethe electromagnet 217 (step S26 in FIG. 4B). Accordingly, the firstblade 1 is held at its aperture opening position by the latch member 11.

Thus, in the motion video (movie) mode, the signal processing circuit204 produces successive video signals corresponding to the motionpicture and these signals can be taken out through the external terminal220. Therefore, it is possible to record the signals on tape byconnecting a VCR (Video Cassette Recorder) to receive the signals fromthe terminal 220. Also, it is possible to monitor the image by using anelectronic view finder connected to receive the signals from theterminal 2. During operation, the control circuit 201 repeatedly checksthe switch 215 to ascertain whether it is open (step S27 in FIG. 4B) andwhen it is found to be open, the control circuit 201 commands theenergization circuit 208 to energize the electromagnet 218 (step S28 inFIG. 4B). Thus, the second blade 2 is rotated in the counterclockwisedirection to close the aperture 10 and to release the locking of thedrive member 14 and hence the latch member 11 by the lock member 22. Thecontrol circuit 251 then commands the energization circuit 208 todeenergize the electromagnet 218 (step S219 in FIG. 4B). Thus, the firstand second blades 1 and 2 are returned in a clockwise direction to theirrespective rest positions by the springs 4 and 5, respectively. Theviewfinder mirror 32 is then returned to its viewing and the mechanismis returned to the condition shown in FIG. 2A.

After the step S29, the control circuit 201 checks the switch 214 toascertain whether it is open (step S30 in FIG. 4B); and if it is foundto be open, the control circuit 201 deactivates the circuits 202 to 205and 210 and ceases the operation (step S31 in FIG. 4B).

A modification of the above explained first embodiment, is shown in FIG.5. Here the link lever 35 may be arranged to be driven in thecounterclockwise direction by the stop down operation of the stop downlever 33 acting through a connecting lever 38 which is pivotally mountedat an axis 39. The connecting lever 38 has a fore end part 38b which isengaged by the stop down lever 33, and a tail end part 38a which engagesa tail end part 35b of the link lever 35.

A second embodiment of the present invention will be explained withreference to FIGS. 6A to 8B. The second embodiment differs from thefirst embodiment only in the manner of releasing of the latching of thefirst shutter blade 1 at its moved position by the latch member 11. Thatis, in the second embodiment, the locking of the drive member 14 by thelock member 22 is released by an electromagnet 40 which is positioned toact upon the arm part 22a of the lock number 22. The electromagnet 40 isarranged to attract the arm part 22a of the lock member 22 as is shownin FIGS. 6A and 6B. As is shown in FIG. 7, the circuit system furthercomprises an energization circuit 222 connected to energize anddeenergize the electromagnet 40 under the control of the control circuit201. The control circuit 201 has control functions for the still and themotion video mode shown in FIGS. 8A and 8B, respectively.

In the still video mode, as is shown in FIG. 8A, the control circuit 201commands the energization circuit 222 to energize the electromagnet 40(step 16) after the step S11. Thus, the electromagnet 40 attracts thearm part 22a of the lock member 22 and thereby causes the lock member 22to rotate in the counterclockwise direction against the spring 24.Accordingly, the drive member 14 is unlocked and is rotated in thecounterclockwise direction by the spring 16. Thus, the latch member 11is rotated in the clockwise direction by the spring and therebyunlatches the first blade 1.

After the step S16, the control circuit 201 commands the energizationcircuit 222 to deenergize the electromagnet 40 (step S17 in FIG. 8A) andthen goes to the step S12 to trigger the shutter control circuit 206.

In the motion video mode, as is shown in FIG. 8B, the control circuit201 commands the energization circuit 222 to energize the electromagnet40 (step S28') after the step 27 (instead of the step S28 in FIG. 4B);and then the control circuit commands the circuit 222 to deenergize theelectromagnet 40 (step S29') (instead of the step S29 in FIG. 4B). Thus,the latching of the first blade 1 is released by the electromagnet 40and the blade 1 returns to its rest position. The control circuit 201then goes to the step S30.

Other than the above, the construction and the manner of the operationof the second embodiment are the same as those of the first embodiment.

Furthermore, as is shown in FIG. 9, the same modification as that shownin FIG. 5 with respect to the first embodiment may be made with respectto the second embodiment.

A third embodiment of the present invention will now be explained withreference to FIGS. 10A and 10B.

As shown in FIGS. 10A and 10B, a latch lever 41 is pivotally mounted atan axis 42 and is urged by a spring 43 in a clockwise direction so thatits arm part 41c strikes on a stopper pin 44. The latch lever 41 isprovided with a claw part 41b on another arm part 41a thereof to arrestthe first shutter blade 1 at its tail end part 1a when the blade 1 isrotated to open the aperture 10. An electromagnet 40' (similar to theelectromagnet 40 in the second embodiment) is arranged to attract thearm part 41a of the latch lever 41 to rotate the lever 41 in acounterclockwise direction against the spring 43.

In the motion video mode, when the electromagnet (217 in FIG. 7) for thefirst blade 1 is energized, the blade 1 is rotated in thecounterclockwise direction against the spring 4, is latched by the clawpart 41b of the latch lever 41, as is shown in FIG. 10B. Then theelectromagnet 217 is deenergized while the blade 1 is kept at therotated position to open the aperture 10. When the apparatus is to bereturned to the aperture closing condition shown in FIG. 10A, theelectromagnet 40 is energized for a predetermined period of time torotate the latch lever 41 in the counterclockwise direction against thespring 43. Thus, the first blade 1 is unlatched and is rotated in theclockwise direction by the spring 4 to close the aperture 10 as is shownin FIG. 10A.

On the other hand, in the still video mode, when the electromagnet 217(FIG. 7) is energized, the first blade 1 is rotated to open the aperture10 and is latched by the latch lever 41 as is shown in FIG. 10B. Then,the electromagnet 217 is deenergized. This condition corresponds to thepreparatory exposure condition and the correction of the shutter speedis performed based on the luminous signal Y. The electromagnet 218 (FIG.7) for the second blade 2 is then energized to rotate the second blade 2in the counterclockwise direction against the spring 5, to close theaperture 10. At the same time, the electromagnet 217 for the first blade1 is again energized. The electromagnet 40 is then energized to releasethe latching of the first blade 1 by the latch lever 41. Thus, theblades 1 and 2 are kept at their respective rotated positions by theelectromagnets 217 and 218, respectively. The shutter control circuit206 (FIG. 7) is then triggered and the electromagnets 218 and 217 aredeenergized by the control circuit 206 at points in time separated by anamount corresponding to the corrected exposure time. This corresponds tothe true exposure. The electromagnet 40 is then deenergized to releasethe latch lever 41.

Thus, as in the case of the third embodiment, the circuit system shownin FIG. 7 can be used in a manner such that the control circuit 201 hasthe control function shown in FIG. 8B for the control of the motionvideo mode and the control function shown in FIG. 8A for the control ofthe still video mode; provided that the steps S17 and S12 are changed intheir order.

A fourth embodiment of the present invention will now be explained withreference to FIGS. 11A to 13B.

In the fourth embodiment, the triggering of the drive member 14 to causethe latch member 11 to latch the first blade 1 is performed by anelectromagnet 46 through the trigger member 19. The electromagnet 46 isarranged to attract the arm part 19a of the drive member 19 to rotatethe member 19 in the clockwise direction.

As is shown in FIG. 12, the electrical circuit system for thisembodiment includes an energization circuit 223 connected to energizethe electromagnet 46 under the control of the control circuit 201.

In the operation of the fourth embodiment, as shown in FIGS. 13A and13B, the control circuit 201 commands the energization circuit 207 toenergize the electromagnet 217 to rotate the first blade 1 in thecounterclockwise direction (S06' in FIG. 13A and S25' in FIG. 13B); andthen the control circuit commands the energization circuit 223 toenergize the electromagnet 46 to rotate the trigger member 19 togetherwith the drive member 14 in the clockwise direction against the spring16 (S18 in FIG. 13A and S32 in FIG. 13B). Thus, the latch member 11 isrotated in the counterclockwise direction against the spring 13 andlatches the first blade 1 at the pin 8 mounted thereon as is shown inFIG. 11B. The control circuit 201 then commands the energization circuit201 to deenergize the electromagnet 46 (S19 in FIG. 13A and S33 in FIG.13B); and thereafter the control circuit commands the energizationcircuit 207 to deenergize the electromagnet 217.

Other than the above, the structure and the function of the system ofthe fourth embodiment are the same as those of the first embodimentshown in FIGS. 2A to 4B.

As will readily be appreciated from foregoing, according to the featureof the various aspects of the present invention, it becomes possible togreatly lessen the consumption of the electrical power which isnecessary to keep the electromagnetic drive shutter opened for a certainperiod of time.

Another embodiment of the present invention will be explained hereinbelow with reference to FIGS. 14 to 17.

In a camera mechanism shown in FIG. 14, a pulse motor 301 is providedfor presetting a stop value (an aperture size) to a diaphragm device tobe explained later. The motor 301 has an output shaft 301a on which agear 301b is mounted. A sector lever 302 is pivotally mounted at an axis302a and has an arm part 302b and a gear part 302c with which the gear301b meshes.

A stop value presetting ring 303 is rotatably held within a lens barrel(not shown) and has a cam part 303a for determining the stop value andan arm part 303b which is engageable with the arm part 302b of thesector lever 302. The presetting ring 303 is urged by a spring 304 in aclockwise direction so that the tip of the arm part 303b strikes againstthe tip of the arm part 302b of the sector lever 302.

A bell crank lever 305 is pivotally mounted on an axis 305c within thelens barrel and has a pair of pins 305a and 305c on both sides thereof,respectively. The pin 305a is arranged to be engageable with the campart 303a of the presetting ring 303.

A diaphragm blade driving ring 306 is also rotatably held within thelens barrel and has a projection 306a, an arm part 306c and a pluralityof holes 306b (only one of them is illustrated in the Fiqure). Thedriving ring 306 is urged by a spring 309 in a clockwise direction sothat the projection 306a engages with the pin 305b of the crank lever305. A diaphragm cam ring 308 is fixedly held within the lens barrel andis provided with a plurality of cam slots 308a (only one of them isillustrated in the Figure). A plurality of diaphragm blades 307 (onlyone of them is illustrated in the Figure) are arranged between thedriving ring 306 and the cam ring 308 and each of which is provided witha pair of pins 307a and 307b on both sides thereof, respectively. Thepins 307a are respectively engaged in the holes 306b of the driving ring306 and the pins 307b are respectively engaged in the cam slots 308a ofthe cam ring 308.

A stop down ring 310 is also rotatably held within the lens barrel andhas a pair of arm parts 310a and 310b. The stop down ring 310 is urgedby a spring 311 in a counterclockwise direction so that the arm part310a rotates through the arm part 306c the driving ring 306 in acounterclockwise direction against the spring 309. A D.C. motor 312 isprovided for operating the diaphragm device and a viewfinder mirroroperating mechanism to be explained later. The motor 312 has a rotorshaft 312a on which a bevel gear 312b is mounted. Another bevel gear 313is meshed with the bevel gear 312a and has a shaft on which threedifferent cam discs 314, 315 and 316 are provided.

A release lever 317 is pivotally mounted on a pin 318b planted on aslide lever 318 and is urged by a spring 319 in a counterclockwisedirection so that its pin 317a abuts on a side of the slide lever 318.The release lever 317 is engageable with a step part 316b of the camdisc 316. The slide lever 318 is slidably guided by pins 320 at itsslots 318c and is urged upward by a spring 321.

A latch lever 322 is pivotally mounted at an axis 322a and is urged by aspring 323 in a counterclockwise direction. A tapered part 318a of theslide lever 318 is engageable with an arm part 322b of the latch lever322.

A mirror retracting lever 324 is pivotably mounted at an axis 324e andis urged by a tension spring 337 in a clockwise direction. The latchlever 322 latches the retracting lever 324 by engaging its step part322c with an arm part 324c of the retracting lever 324 in a conditionwhere the spring 337 is charged (i.e. tensioned). A stopper pin 358 isprovided to limit the clockwise movement of the retracting lever 324. Aclutch lever 325 is pivotally mounted on a pin 324d mounted on theretracting lever 324 and is urged by a spring 326 in a clockwisedirection (as viewed from above).

A viewfinder mirror operating lever 327 is pivotally mounted on an axis327d and is urged by a spring 338 in a counterclockwise direction. Astopper pin 353 is provided for the operating lever 327. A hook part325a of the clutch lever 325 is engageable with a pin 327a planted onthe operating lever 327. The arm part 310b of the stop down ring 310 isreceived by a bent up part 327c of the operating lever 327.

A viewfinder mirror supporting lever 328 is pivotally mounted on an axis328c and is supporting a view finder mirror 329 at its inclined end part328b so that the mirror 329 is held in a predetermined inclinedcondition with respect to a picture taking optical axis O. Thesupporting lever 328 is engaged with a pin 327b planted on the operatinglever 327 at its fork part 328a provided on another end thereof. Themirror 329 is held at a predetermined viewing position in the opticalpath when the operating lever 327 is pivotted by the spring 338 in thecounterclockwise direction until it is restricted by the stopper pin353. In this condition, the stop down ring 310 keeps the diaphragmdevice at its fully opened state.

A link lever 330 is pivotally mounted on an axis 330c and its fore endpart 330a is engageable with a projection 314a of the first cam disc314. A clutch release lever 331 is pivotally mounted on an axis 331c andis urged by a spring 332 in a counterclockwise direction so that its endpart 331b strikes against a tail end part 330b of the link lever 330. Apin 331a planted on another end part of the release lever 331 isengageable with an arm part 325b of the clutch lever 325.

A charge lever 333 is pivotally mounted on an axis 333c and is urged bya spring 357 in a counterclockwise direction so that a cam follower part333a at its fore end engages with a charge cam part 316a of the thirdcam disc 316. A tail end part 333b of the charge lever 333 is engageablewith an arm part 324a of the retracting lever 324.

A stop lever 334 is pivotally mounted on an axis 334c and is urged by aspring 335 in a clockwise direction so that a hook part 334a engageswith a recess part 315a of the second cam disc 315 when it confrontstherewith. A normally open switch 336 is arranged to be closed by a tailend part 334b of the stop lever 334 when its hook part 334a engages intothe recess 315a of the cam disc 315 and thus the disc 315 is stopped itsrotation.

There are provided an optical low pass filter 339 (a crystal filter) andan image pickup element 351 (such as a CCD) in the optical path. Betweenthe optical filter 339 and the image pickup element 351, there areprovided a pair of shutter blades 340 and 341. These shutter blades 340and 341 are pivotally mounted on a common axis 340c and are respectivelyurged by springs 342 and 343 in a clockwise direction. Stopper pins 340band 341b are respectively provided for the shutter blades 340 and 341.The blades 340 and 341 are provided with driving coils 344 and 345,respectively, and there are also provided permanent magnets 346 and 347for the coils 344 and 345, respectively. The first shutter blade 340,when it is rotated in the clockwise direction by the spring 342 until itstrikes on the stopper pin 340b, closes a picture taking aperture 352provided in front of the image pickup element 351 and when the coil 344is energized, the blade 340 is rotated in the counterclockwise directionagainst the spring 342 and opens the aperture 352. The second shutterblade 341, when it is rotated in the clockwise direction by the spring343 until it is restricted by the stopper pin 321b, opens the aperture352 and when the coil 345 is energized, the blade 341 is rotated in thecounterclockwise direction against the spring 343 and closes theaperture 352.

A shutter blade latch lever 348 is pivotally mounted on an axis 348d andis urged by a spring 349 in a clockwise direction so that it strikes ona stopper pin 350. The latch lever 348 is provided with a claw part 348ato latch the first shutter blade 340 at its tail end part 340a when itis rotated in the counterclockwise direction and opens the aperture 352.The second shutter blade 341 is provided with a bent back part 341a atits tail end part which strikes on an arm part 348b of the latch lever348 and rotates the same to cause the claw part 348a to release thelatching of the first shutter blade 340 when the second shutter blade341 is rotated in the counterclockwise direction.

An arresting lever 354 is pivotally mounted on an axis 354c and is urgedby a spring 355 in a clockwise direction. The arresting lever 354 isprovided with a hook part 354a to arrest the latch lever 348 at its armpart 348c. A release lever 356 is pivotally mounted on an axis 356c andis urged by a spring 357 in a clockwise direction so that its end parts356a and 356b strike against an arm part 324b of the retracting lever324 and a tail end part 354b of the arresting lever 354, respectively.

Next, in a circuit system shown in FIG. 15, a synchronization signalgeneration circuit 402 (SSG hereinafter) is provided for generatingsynchronization signals. A drive circuit 403 is connected to drive theimage pickup element 351 in response to the synchronization signalsupplied by the SSG circuit 402. A signal processing circuit 404 ofknown circuit construction is connected to receive and process theoutput signal of the image pickup element 351. A video floppy discrecording device 416 of known construction is connected to receive andrecord the output signal of the processing circuit 404.

A shutter speed setting circuit 405 is provided for setting a desiredshutter speed. A shutter control circuit 406 of a known construction isconnected to control the deenergization of the coils 344 and 345 inresponse to the output signal of the shutter speed setting circuit 405and the synchronization signal supplied from the SSG 402. Energizationcircuits 407 and 408 are respectively arranged to energize the coils 344and 345 in response to the control signal supplied from a controlcircuit 401 and deenergize the coils 344 and 345 in response to thecontrol signal supplied from the shutter control circuit 406.

A correction circuit 409 is connected to supply a shutter speedcorrection signal to the shutter speed setting circuit 405 based on aluminous signal Y supplied by the signal processing circuit 404. A stopvalue determination circuit 410 of a known construction is connected toreceive a shutter speed signal Tv supplied from the shutter speedsetting circuit 405 and an object brightness signal Bv supplied by anobject brightness measuring element (photocell) 411. The measuringelement 411 may be positioned to receive an object light via the viewfinder mirror 329 when it is at the position on the optical axis O as isshown in FIG. 14.

A pulse motor control circuit 412 is connected to control the pulsemotor 301 in response to a stop value signal Av supplied from thedetermination circuit 410. A D.C. motor drive circuit 413 drives themotor 312 under the control of the control circuit 401. The controlcircuit 401 controls the entire circuit system based on the conditionsof switches 414, 415 and 336. The first and second trigger switches 414and 415 are each of the normally open type and are arranged to be closedby a first and a second step of the depression of a trigger button 417,respectively. The control circuit 401 may comprise a micro computer. Thecontrol circuit 401 has a control function shown by the flow chart ofFIG. 16.

Next, the operation of this embodiment will be explained with referenceto FIGS. 14 to 16.

While the apparatus is in its charged condition as shown in FIG. 14, thecontrol circuit 401 (FIG. 15) checks the first trigger switch 414 toascertain whether it is closed by the depression of the trigger button417 to the extent of the first step (step S01 in FIG. 16). If the switch414 is found to be closed, the control circuit 401 causes the circuits402, 403, 404, 405 and 410 to operate (step S02 in FIG. 16). Thus, theSSG circuit 402 begins to generate the synchronization signals and thedrive circuit 403 also begins to drive the pickup element 351 based onthe supplied synchronization signal. The output signal of the pickupelement 351 is processed in the processing circuit 404 based on thesynchronization signals supplied from the SSG circuit 402. On the otherhand, the stop value determination circuit 410 determines theappropriate stop value based on the object brightness signal Bv suppliedby the brightness measuring element 411 and the shutter speed signal Tvsupplied by the shutter speed setting circuit 405 in accordance with thepreset shutter speed set to the circuit 405, and produces the stop valuesignal Av corresponding to the determined stop value. In response to thestop value signal Av, the pulse motor control circuit 412 operates thepulse motor 301 to adjust the rotational position of the stop valuepresetting ring 303 through the sector lever 302 in accordance with thestop value represented by the signal Av. Thus, the stop value determinedby the determination circuit 410 is preset to the diaphragm device.

The control circuit 401 waits for a time period of t₁ (step S03 in FIG.16) which is sufficient for the completion of the above explained stopvalue determination and presetting operation and then checks the secondtrigger switch 415 to ascertain whether it is closed by the depressionof the trigger button 417 to the extent of the second step (step S04 inFIG. 16). If the switch 415 is found to be closed, the control circuit401 causes the stop value determination circuit 410 to hold thedetermined stop value (step S05 in FIG. 16). Then, the control circuit401 commands the motor drive circuit 413 to cause the motor 312 torotate in the counterclockwise direction in FIG. 14 (step S06 in FIG.16).

When the motor 312 rotates in the counterclockwise direction, the camdiscs 314, 315 and 316 are rotated in the clockwise direction throughthe bevel gears 312b and 313. As a result, the third cam disc 316depresses, through its step part 316b, the release lever 317 togetherwith the slide lever 318 against spring 321. When the slide lever 318 isdepressed, its tapered part 318a engages the latch lever 322 and rotatesin the clockwise direction against the spring 323. As a result, the steppart 322c of the latch lever 322 releases the retracting lever 324. Theretracting lever 324 is then rotated in the clockwise direction by thespring 337. The retracting lever carries with it the clutch lever 325which in turn rotates the mirror operating lever 327 in the clockwisedirection against the spring 338. The mirror supporting lever 328 isthus rotated in the clockwise direction to retract the viewfinder mirror329 from the optical path.

At the same time, the stop down ring 310 is pressed at its arm part 310bby the bent up part 327c of the operating lever 327 and is rotated inthe clockwise direction against the spring 311. This allows the bladedriving ring 306 to be rotated in the clockwise direction by the spring309 until its projection 306a engages the 305b of the crank lever 305and swings it to bring the pin 305b against the cam part 303a of thepresetting ring 303. Thus, the diaphragm device is stopped down and thediaphragm blades 307 form an aperture corresponding to the stop valuedetermined by the stop value determination circuit 410 and presetthrough the presetting ring 303.

On the other hand, when the retracting lever 324 rotates in theclockwise direction, the stop lever 334 is pressed at its lower end part334b by the arm part 324a of the retracting lever 324 and is rotated inthe counterclockwise direction against the spring 335. Thus, the hookpart 334a of the stop lever 334 is pulled away from the recess part 315aof the second cam disc 315. At the same time the normally open switch336 is allowed to open. The control circuit 401, after the step S06 inFIG. 16, repeatedly checks the switch 336 to ascertain whether it isopen (step S07 in FIG. 3); and if the switch 336 is ascertained to beopen, the control circuit 401 commands the motor drive circuit 413 tocause the motor 312 to stop (step S08 in FIG. 16).

The control circuit 401 then commands the energization circuit 407 toenergize the coil 344 of the first shutter blade 340 for a time periodof t₂ (step S09 in FIG. 16). Thus, the first shutter blade 340 isrotated in the counterclockwise direction against the spring 342 bymagnetic repulsion generated between the coil 344 and the permanentmagnet 346 and is latched at its tail end part 340a by the claw part348a of the latch lever 348. When the time period of t₂ has elapsed, thecontrol circuit 401 commands the energization circuit 407 to deenergizethe coil 344 (step S10 in FIG. 16). The time period of t₂ is selected tobe sufficient for the first shutter blade 340 to be rotated in thecounterclockwise direction and latched by the latch lever 348. Thus, theaperture 352 is kept opened; and while the aperture is in thiscondition, the control circuit 401 causes the correction circuit 409 tooperate (step S11 in FIG. 16). The correction circuit 409 detects theluminosity of the object scene based on the luminous signal Y suppliedby the signal processing circuit 404 and produces the shutter speedcorrection signal. In response to this correction signal, the shutterspeed setting circuit 405 corrects the set shutter speed and provides acorrected shutter speed signal to the shutter control circuit 406. Afterthe step S11, the control circuit 401 waits for a time period of t₃(step S12 in FIG. 16) which is sufficient for the completion of theabove explained shutter speed correction operation and then causes thecorrection circuit 409 to hold the correction signal (step S13 in FIG.16).

The control circuit 401 then commands the energization circuits 407 and408 to energize the coils 344 and 345 (step S14 in FIG. 16). When thecoil 345 is energized, the second shutter blade 341 is rotated in thecounterclockwise direction against the spring 343 by the magnetic forceof repulsion generated between the coil 345 and the permanent magnet347; and the shutter blade 341 closes the aperture 352. At this time,the bent back part 341a of the second shutter blade 341 presses thelatch lever 348 at its arm part 348b to rotate the latch lever 348 inthe counterclockwise direction against the spring 349. Thus, the clawpart 348a of the latch 348 unlatches the first shutter blade 340; butthe blade 340 is kept at the counterclockwisely rotated state by themagnetic force of repulsion generated between the coil 344 and themagnet 346. On the other hand, the latch lever 348 is arrested at itscounterclockwisely rotated state by the arresting lever 354 since thearresting lever 354 is switched to an operative position by the spring355 due to the counterclockwise rotation of the release lever 356responding to the clockwise rotation of the arm part 324b of theretracting lever 324.

The control circuit 401 then triggers the shutter control circuit 406(step S15 in FIG. 16). When triggered, the shutter control circuit 406causes, in response to the vertical synchronization signal supplied bythe SSG circuit 402 right after the triggering, the energization circuit408 to deenergize the coil 345. Then, after the time lag correspondingto the shutter speed (exposure time) indicated by the corrected shutterspeed signal supplied by the shutter speed setting circuit 405, theshutter control circuit 406 causes the energization circuit 407 todeenergize the coil 344. Thus, the second and the first shutter blades341 and 340 are rotated in the clockwise direction by their respectivesprings 343 and 342 at times separated by the above mentioned time lag;and by this, the image pickup element 351 is exposed to the object lightfor a time period corresponding to such time lag. The image signalgenerated in the pickup element 351 in response to the light exposure isread out and supplied to the recording device 416 after being processedby the signal processing circuit 404 during the field period nextfollowing that in which the exposure of the pickup element 351 has beencarried out. Therefore, before commencement of the reading out of theimage signal from the pickup element 351 after the exposure thereof, thecontrol circuit 401 triggers the recording device 416 (step S16 in FIG.16); and by this, the recording device 416 records on the floppy discthe image signal supplied by the processing circuit 404 andcorresponding to one TV field, based on the synchronization signalsupplied by the SSG circuit 402.

After the signal recording by the recording device 416, the controlcircuit 401 checks the switch 414 to ascertain whether it is open (stepS17 in FIG. 16). If the switch 414 is ascertained to be open, thecontrol circuit 401 deactivates the circuits 402, 403, 404, 405, 409 and410 (step S18 in FIG. 16). Then the control circuit 401 commands themotor drive circuit 413 to cause the motor 312 to rotate in theclockwise direction (step 19 in FIG. 16). This clockwise rotation of itsmotor 312 rotates the cam discs 314, 315 and 316 in the counterclockwisedirection through the bevel gears 312b and 313. At the same time, theprojection 314a on the cam disc 314 causes the link lever 330 to rotatein the counterclockwise direction. By this, the release lever 331 isrotated in the clockwise direction against the spring 332 and the pin331a of the release lever 331 causes the clutch lever 325 to rotate inthe counterclockwise direction against the spring 326 and to release theoperating lever 327. This allows the operating lever 327 to be rotatedin the counterclockwise direction by the spring 338 until it isrestricted by the stopper pin 353. By this, the supporting lever 328 isrotated in the counterclockwise direction to bring the mirror 329 to theviewing position in the optical path. At the same time, the stop downring 310 follows the operating lever 327 and is rotated in thecounterclockwise direction by the spring 311 while hauling the drivingring 306 in the same direction against the spring 309. Thus, thediaphragm device is fully opened.

On the other hand, by the counterclockwise rotation of the cam disc 316,the charge lever 333 is rotated in the clockwise direction against thespring 357; and the lower end 333b of the charge lever 333 engages thearm part 324a of the retracting lever 324 and rotates the retractinglever 324 in the counterclockwise direction against the spring 337. Bythis, the stop lever 334 is freed from engagement with the arm part 324aof the retracting lever 324 and becomes free to engage with the cam disc315 by the action of the spring 335. When the retracting lever 324 isrotated to a predetermined position, the arm part 325a of the clutchlever 325 engages with the pin 327a on the operating lever 327. At thesame time, the step part 322c of the latch lever 322 latches the arm324c of the retracting lever 324 and holds the retracting lever againstthe charged spring 337. On the other hand, the release lever 356 isfreed from engagement with the arm part 324b of the retracting lever324; and this allows the release lever 356 to be rotated in theclockwise direction by the spring 357. This causes the arresting lever354 to rotate in the counterclockwise direction against the spring 355and to release the latch lever 348. Thus, the latch lever 348 is rotatedin the clockwise direction by the spring 349 until it is restricted bythe stopper pin 350. Although, at the final stage of thecounterclockwise rotation of the cam disc 316, the highest lift portionof the cam disc 316 engages with the release lever 317, the releaselever 317 is free to rotate in the clockwise direction and does notobstruct the cam disc 316.

After the retracting lever 324 has been latched by the latch lever 322with the spring 337 being charged, the cam disc 315 rotates until itsrecess 315a confronts the hook part 334a. of the stop lever 334. Thehook part 334a engages the recess 315a and stops the cam disc 315. Atthe same time, the tail end part 334b of the stop lever 334 closes theswitch 336. On the other hand, after the step S19, the control circuit401 repeatedly checks the switch 336 to ascertain whether it is closed(step S20 in FIG. 16); and if it is ascertained to be closed, thecontrol circuit 401 commands the motor drive circuit 413 to stop themotor 312 (step S21 in FIG. 16). This ends the operation.

FIG. 17 illustrates the timings of the operations of the elements inFIGS. 14 and 15.

In the embodiment of FIGS. 14 and 15, though the correction of theexposure value is arranged to be carried out by controlling shutterspeed (i.e. the exposure time) based on the luminous signal Y, thecorrection may be carried out by controlling the stop value (i.e. theaperture size) or both shutter speed and aperture size based on theluminous signal Y.

As will be appreciated from foregoing, in the above describedembodiment, mirror retraction and mirror return are performed by usingthe normal (or reverse) and the reverse (or normal) rotation of themotor, respectively. Therefore, the mirror operating mechanism and thecamera mechanism are simplified. Moreover, they can be small in size andreliable in their operation.

Further, the features of the present embodiment, especially the mirrordrive mechanism using a reversible motor may be used in a correspondingmechanism in a film camera.

A sixth embodiment of the present invention will now be explained withreference to FIGS. 18 to 21. The sixth embodiment includes the followingconstruction in addition to that of the first embodiment explainedabove.

In the camera mechanism shown in FIGS. 18 and 19, a slide knob 360 isattached to a tail end part of a slide plate 361 which is slidablyguided by a pair of pins 362 at slots 361a of the slide plate. The slideplate 361 is urged by a spring 365 in the rightward direction. A foreend part 361c of the slide plate 361 faces the operating lever 327 sothat it rotates the lever 327 in the clockwise direction against thespring 338 when the plate 361 is slid leftward against the spring 365.Moreover, a downward projection part 361b of the slide plate 361 isprovided for closing a normally open type switch 369 when the plate 361is slid to its leftward position. A slide lever 363 is slidably guidedby a pair of pins 364 at slots 363a thereof and is urged upwardly by aspring 366. A tail end part 363c of the lever 363 rides on a cam part361d of the slide plate 361 while a fore end part 363b of the lever 363faces an arm part 340d of the first shutter blade 340 so that it rotatesthe blade 340 against the spring 342 to open the aperture 352 when thelever 363 is moved upward by the action of the cam part 361d of theplate 361 when the plate is moved to its leftward postion. A stopper pin367 is held by a leaf spring 368 and is engageable with an edge part360a of the knob 360 to keep the same at its leftward position as shownin FIG. 19.

In a circuit system shown in FIG. 20, the switch 369 is connected to thecontrol circuit 401. The control circuit 401 selects the operation modeof the system, i.e. either a still video mode or a motion video (movie)mode, depending upon the state of the switch 369. Moreover, there isprovided an external output terminal 418 connected to the output of thesignal processing circuit 404 to provide remote output of the videosignal from the circuit 404. Furthermore, in this embodiment, the objectbrightness measuring element 411 is positioned so as to receive theobject light through the diaphragm device but not through the viewfinder mirror 329.

Other than the above, the same construction shown in FIGS. 14 and 15 isused in the embodiment of FIGS. 18-20.

In this embodiment, if the knob 360 is not pushed leftward, the cameraoperates in the same way as that of the first embodiment. In this case,the control circuit 401 checks switch 369 to ascertain whether it isopen (step S22 in FIG. 21) after the switch 414 is ascertained to beclosed at the step S01 in FIG. 21. If the switch 369 is open, thecontrol circuit 401 goes to the step S02 in FIG. 21. Thus, still videorecording is performed.

On the other hand, if the knob 360 is pushed leftward as shown in FIG.19, the slide plate 361 is slid in the same direction and rotates theoperating lever 327 in the clockwise direction. Thus, the mirror 329 isretracted from the optical path and the diaphragm device is stopped downthrough the stop down ring 310. At the same time, the projecting part361b closes the switch 369 while the slide lever 363 is moved upward bythe action of the cam part 361d of the plate 361 to push up the firstshutter blade 340. Thus, the aperture 352 is opened and the blade 340 isheld at a position just before the position at which it becomes latchedby the latch lever 348. Moreover, the knob 360 is retained at itspushed-in position by the stopper pin 367 which protrudes by the spring368 to engage with the edge part 360a of the knob 360.

In this condition, when the first trigger switch 414 is closed (step S01in FIG. 21), the control circuit checks the switch 369 to ascertainwhether it is open (step S22 in FIG. 21). If it is found not open, thecontrol circuit 401 causes the shutter speed setting circuit 405 to setthe shutter speed (exposure time) (Tv) at 1/60 sec. (step S23 in FIG.21) and then activates the circuits 402 or 404 and 410 (step S24 in FIG.16). Thus, in this case, the stop value determination circuit 410determines or controls the stop value (Av) based on the brightnesssignal Bv applied by the measuring elements 411 which receives theobject light through the stopped down diaphragm device and the shutterspeed signal Tv representing an exposure time of 1/60 sec. whichcorresponds to the TV field rate under the standard NTSC system.(Therefore, under the standard PAL system, an exposure time of 1/50 sec.may be preferable.) In accordance with the stop value signal Av producedby the determination circuit 410, the motor control circuit 412 controlsthe pulse motor 301 to adjust the diaphragm aperture of the diaphragmdevice.

Thus, in the motion video (movie) mode, the signal processing circuit404 produces a succession of video signals corresponding to the motionpicture and these signals can be taken out through the external terminal418. Therefore, it is possible to record the signals on tape byconnecting a VCR (Video Cassette Recorder) to receive the signals fromthe terminal 418. Also, it is possible to monitor the image by using anelectronic view finder connected to receive the signals from theterminal 418.

During operation of the apparatus, the control circuit 401 repeatedlychecks the switch 414 to ascertain whether it is open (step S25 in FIG.21); and if it is found to be open, the control circuit 401 deactivatesthe circuits 402 to 405 and 410 to stop the operation (step S26 in FIG.21).

When it is desired to return to the still video mode from the motionvideo mode, this change over is done simply by pushing the stopper pin367 against the leaf spring 368 and releasing the restriction of theknob 360 by the pin 367. That is, when released, the knob 360 and theslide plate 361 are moved in the rightward direction by the spring 362and the slide plate releases the operating lever 327. Thus, the lever327 is rotated in the counterclockwise direction by the spring 338 tobring the mirror 329 into the optical path and to release the pressingof the arm part 506 of the stop ring 310. Moreover, the projecting part361b of the plate 361 allows the switch 369 to open. Furthermore, theslide lever 363 descends along the surface of the cam part 361d of theplate 361 and releases first shutter blade 340. Thus, the blade 340closes the aperture 352 and the condition for still video recordingshown in FIG. 18 is attained.

As will be appreciated from foregoing, in the present embodiment, it ispossible to utilize the still video recording camera as a motion videocamera by addition of a simple mechanical construction. Moreover, thesame advantage as that in the first embodiment is also obtained in thesecond embodiment.

Next, a seventh embodiment of the present invention will be explainedhereinbelow with reference to FIGS. 22 to 26.

In a camera mechanism shown in FIG. 22, a solid state image pickupelement 511 such as a CCD is arranged to receive an image light througha shutter device described hereinbelow. A shutter base plate 512 isfixedly arranged in front of the pickup element 511 and is provided withan aperture 512a. First and second shutter blades 513 and 514 arearranged to move on the base plate 512 with respect to the aperture 512ato open and close the same. The first and the second blades 513 and 514respectively constitute parallel link mechanisms together with armmembers 515 and 516; and 517 and 518; and are urged downwardly bysprings (not shown). Each of the arm members 515 to 518 is pivotallysupported on the base plate 512 at respective axes 515a, 516a, 517a and518a. The arm members 515 and 517 are respectively provided with pins515b and 517b and arranged to be latched by respective latch members(not shown) in the charged condition shown in the FIG. 22. There arealso provided electromagnets (not shown) for the respective latchmembers to unlatch the latching of the arm members 515 and 517,respectively. When the arm members 515 and 517 are unlatched, the blades513 and 514 are moved respectively by the charged springs. The abovedescribed shutter operating mechanism is well known in the art,especially in the field of the single lens reflex camera.

A normally open type switch 520 is arranged on the base plate 512 sothat its contact piece 520a is pushed by a tail part of the arm member515 and contacts with another contact piece 520b to close the circuitwhen the first blade 513 starts to open the aperture 512a.

A viewfinder mirror 521 is pivotally mounted on a shaft member 522 andis urged by a spring (not shown) in a counterclockwise direction so thatit is placed at a viewing position in the optical path. A stopper pin521a is provided for the mirror 521. The mirror 521 is provided withpins 521a and 521b on both sides. The pin 521a is engageable with aprojected part 534c of an unlatch lever 534. A mirror drive base plate523 is fixedly arranged on the side of the mirror 521. A main drivelever 524 is pivotally mounted on the base plate 523 at an axis 524a andis urged by a spring 525 in a counterclockwise direction. A mirror drivelever 528 is also pivotally mounted on the base plate 523 at the axis524a and is urged by a spring 529 in a clockwise direction. An arm part528a of the mirror drive lever 528 is arranged to engage with the pin521a of the mirror 521 to push up the same. Thus the mirror 521 isrotated in a clockwise direction to be retracted from an optical pathagainst its spring (not shown). A haul lever 530 is pivotally mounted onan arm part 524b of the main drive lever 524 at an axis 530a and isurged by a spring 531 in a clockwise direction with respect to the lever524. In the charged condition shown in FIG. 22, a bent part 530b of thehaul lever 530 is engaged with a step part 528b of the mirror drivelever 528. A latch lever 526 is pivotally mounted on the base plate 523at an axis 526a and is urged by a spring 527 in a clockwise direction.In the charged condition shown in FIG. 22, a step part 526b of the latchlever 526 is engaged with an arm part 524c of the main drive lever 524.A mirror return lever 532 is pivotally mounted on the base plate 523 atan axis 532a and is urged by a spring 513 in a clockwise direction. Oneend part, 532b of the return lever 532 is engaged with an arm part 562bof a cam follower lever 562 and another end part 532c of the lever 532is engageable with an end part 530c of the haul lever 530. The unlatchlever 534 is mounted on the base plate 523 at an axis 534a and is urgedby a spring 535 in a counterclockwise direction. A stopper pin 574 isfixedly provided on the base plate 523 for the unlatch lever 534. Theunlatch lever 534 is arranged to be rotated in a clockwise direction bybeing pushed up by the pin 521a of the mirror 521 at the projected part534c thereof when the mirror 521 is retracted from the optical path. Anarm part 534b of the lever 534 is engageable with an arm part 560b of alatch lever 560 and rotates the lever 560 in a counterclockwisedirection against a spring 561 when the lever 534 is rotated in theclockwise direction by the pin 521a. A normally open switch 564 isarranged so that its contact piece 564a is pushed by the pin 521b of themirror 521 and contacts another contact piece 564b to close the circuitat the completion of retraction of the mirror 521 from the optical path.

A base plate 536 is arranged below the mirror 521. An electromagnet 537is fixedly arranged on the base plate 536 and has coils 537a andpermanent magnets 537b. when the coils 537a are energized, the magneticattractive forces of the magnets 537b are decreased to release anarmature 543. A charge lever 538 is pivotally mounted on the base plate536 by an axis 538a and has an arm part 538b which is engageable with anarm part 524d of the main drive lever 524 and with a pin 556c of a maincharge lever 556. A start lever 541 is pivotally mounted on the baseplate 536 at an axis 541a and is urged by an spring 542 in a clockwisedirection. The armature 543 is fixedly mounted on an end part of thestart lever 541. In the charged condition shown in the Figure, thearmature 543 is atracted by the electromagnet 537 and thus the startlever 541 is rotated in a counterclockwise direction against the spring542. Arm parts 541b and 541c of the start lever 541 are respectivelyengageable with a pin 538c planted on the charge lever 538 and an endpart 526c of the latch lever 526.

A motor 551 is provided for charging the mechanisms. An output shaft551a of the motor 551 is connected to a gear 553 through a gear train552. The gear 553 is fixedly attached to a rotation shaft 554. Cams 555,557 and 558 are also fixedly attached to the shaft 554. The main chargelever 556 is pivotally mounted on a camera frame at an axis 556a and isurged at a spring 572 in a counterclockwise direction. The lever 556 hasa cam follower pin 556b which is engageable with the cam 555. When thecam 555 is rotated in a clockwise direction, the main charge lever 556is rotated in a clockwise direction and thus the charge lever 538 isrotated in a counterclockwise direction through the pin 556c of thelever 556.

The latch lever 560 is pivotally mounted on a camera frame at an axis565a and is urged by the spring 561 in a clockwise direction. The lever560 has a hook part 560a which is engageable in a recess 557a providedon the cam 557. The lever 560 also has a pin 560c which is engageablewith and operates a normally open type switch 563. The recess 557a onthe cam 557 is provided so that it faces the hook part 560a of the lever560 at the completion of the charging. At that time the hook part 560aengages the recess 557a to latch the cam 557 and hence the shaft 554.The switch 563 has three contact pieces 563a, 563b and 563c which arenormally separate from each other or when released from pressing by thepin 560c of the latch lever 560 upon rotation of the lever 560 in thecounterclockwise direction by the arm part 534b of the unlatch lever534, as is shown in FIG. 24B. The contact pieces of the switch 563 arebrought into contact with each other by being pressed by the pin 560cwhen the lever 560 rotates in the clockwise direction to a position atwhich its hook part 560a engages with the recess 557a of the cam 557, asis shown in FIG. 24A.

A cam follower lever 562 is pivotally mounted on a camera frame at theaxis 565 together with the latch lever 560. The cam follower lever has acam follower part 562a which is engageable with the cam 558 and an armpart 562b which is engageable with an arm part 532b of the return lever532.

A mirror retracting lever 566 is pivotally mounted on the base plate 536at an axis 568 and is urged by a spring 569 in a counterclockwisedirection. A pin 567 is planted on an end part of one arm of the lever566 and is engageable with a bent out part 528c of the mirror drivelever 528 to rotate the same in the counterclockwise direction when thelever 566 is rotated in a clockwise direction against the spring 569. Astopper pin 573 is fixedly provided on the base plate 536 for the lever566. The lever 566 has a bent up part 566a to receive tail ends 570b and571b of detection pins 570 and 571. As is shown in FIG. 23, face ends570a and 571a of the detection pins 570 and 571 are respectivelyprovided to protrude into sockets 501 and 502. The sockets 501 and 502are provided on a camera housing 500 for connecting an EVF unit and anNTSC adaptor unit, respectively. When the EVF unit and/or the NTSCadaptor unit are connected to the sockets 501 and/or 502, respectively,the pins 570 and/or 571 are pushed in the leftward direction to causethe mirror retracting lever 566 to rotate in the clockwise directionagainst the spring 569. A normally open type switch 575 having contactpieces 575a and 575b is arranged to be closed by an arm part 566c of thelever 566 when the lever 566 is rotated in the clockwise direction bythe pins 570 and/or 571.

A motor 504 is provided for driving a video floppy disc.

Next, in the circuit system shown in FIG. 25, a timing signal generationcircuit 505 is provided for generating different kinds of timing signalsincluding TV synchronization signals. A drive circuit 506 is connectedto drive the image pickup element 511 in response to the timing signalssupplied by the generation circuit 505. An image signal processingcircuit 501 is connected to receive and process output signals from theimage pickup element 511. A recording signal processing circuit 602 isconnected to receive and process output signals from the image signalprocessing circuit 601. The sockets 501 and 502 are also respectivelyconnected to receive output signals from the image signal processingcircuit 601. A gate circuit 603 is connected to receive output signalsfrom the recording signal processing circuit 602. A recording amplifier604 is connected to receive output signals from the gate circuit 603. Amagnetic head 505 is connected to receive output signals from theamplifier 604 to record the signals on a magnetic floppy disc 503. Thedisc 503 is mounted on an output shaft of the motor 504 at its centerhub 503a. A motor control circuit 612 is connected to control therotation speed and phase of the disc 503 through the motor 504 on thebasis of the vertical synchronization signal Vo supplied by thegeneration circuit 605 and a rotation phase signal generated by arotation detection 613 at a particular phase in one revolution of thedisc 613 in a known manner. The motor control circuit 612 is arranged toprovide a servo lock signal SL to a sequence control circuit 607 whenthe rotation of the disc 503 substantially reaches a predetermined speedand a predetermined phase relationship relative to the verticalsynchronization signal V_(D). A head shift mechanism 611 is connected tobe driven by the motor 551 to shift the head 505 to a next recordingposition on the disc 503. A charge mechanism represented by 610, forcharging the exposure system is also connected to be driven by the motor551 as explained hereinbefore. A motor drive circuit 609 is connected todrive the motor 551 under the control of the control circuit 607. Thecontact pieces 563a and 563b of the switch 563 are connected to themotor drive circuit 609 to make a short circuit for the motor 551 whenthey contact each other. The contact piece 563c of the switch 563 isconnected to the control circuit 607.

A light measuring circuit 614 of known construction is provided forproducing an object brightness signal. An automatic lighting control(ALC hereinafter) circuit 623 of known construction is arranged toprovide an object brightness signal based on a luminous signal Yproduced by the image signal processing circuit 601. A selection switchcircuit 624 is connected to select one of the output signals of thecircuits 614 and 623 under the control of the control circuit 607. Ashutter speed setting circuit 616 is provided for setting a desiredshutter speed (exposure time) no longer than the field period (1/60 sec.for NTSC). A diaphragm control circuit 615 is connected to receiveoutput signals from the circuits 616 and 624 to determine and control adiaphragm aperture sized based thereon. A shutter control circuit 617 isconnected to control, based on the output signal of the setting circuit616 and under the control of the control circuit 607, the energizationof coils 618 and 619 of electromagnets respectively provided forunlatching the first and the second shutter blades 513 and 514. Anenergization circuit 625 is connected to energize the coil 537a of theelectromagnet 537 under the control of the control circuit 607.

First and second trigger switches 620 and 621 are connected to thecontrol circuit 607 together with the switches 520, 564 and 575. Thecontrol circuit 607 controls the entire circuit system based on theconditions of the switches 620, 621, 520, 564 and 575. The first and thesecond trigger type switches 620 and 629 are respectively of normallyopen type and are arranged to be closed by a first and a second steprespectively, of the depression of a trigger button 576. The controlcircuit 607 may comprise a micro computer. The control circuit 607 has acontrol function shown by the flow chart of FIG. 26.

A diaphragm device shown in FIGS. 2A and 2B, FIG. 5, FIGS. 6A and 6B,FIG. 9, FIGS. 10A and 10B, FIGS. 11A and 11B, FIG. 14 or FIG. 1 may beused in this embodiment.

Next, the operation of this embodiment will be explained with referenceto FIGS. 22 to 26.

When a power switch (not shown) is closed while the apparatus is in thecharged condition shown in FIG. 22, the control circuit 607 checks thefirst trigger switch 620 to ascertain whether it is closed by thedepression of the trigger button 576 to the extent of the first step(step S31 in FIG. 26). If the switch 620 is ascertained to be closed,the control circuit 607 then checks the switch 575 to ascertain whetherit is open (step S32 in FIG. 26). If the switch 575 is found to be open,this means the designation of a still video recording mode and thecontrol circuit 607 then causes the switch circuit 624 to connect itsoutput to its input terminal a (the output of the light measuringcircuit 614) and causes the control signal CT to the shutter controlcircuit 617 to become low so that the shutter control circuit 617controls the shutter based on the output signal of the setting circuit616 (step S33 in FIG. 26). Here, the necessary circuits have beensupplied with power by the closure of the power switch (not shown).

After the step S33, the control circuit 607 activates the circuits 605,612 and 615. By this, the timing signal generation circuit 605 begins togenerate the timing signals, including the TV synchronization signals;and based on the timing signals generated by the generation circuit 605,the drive circuit 606 begins to drive the pickup element 511. In thiscondition, however, no image light impinges upon the pickup element 511since the view finder mirror 521 is set at the viewing position in theoptical path and also the aperture 512a is closed by the first shutterblade 513. On the other hand, the diaphragm control circuit 615determines the aperture size (stop value) based on the object brightnessinformation supplied by the light measuring circuit 614 through theswitch circuit 624 and the shutter speed information supplied by theshutter speed setting circuit 616. The diaphram control circuit 615controls the diaphragm device according to the thus determined aperturesize. Further, the motor control circuit 612 begins to operate the motor504 to rotate the disc 503 relative to the head 505. The motor controlcircuit 612 is arranged to control the rotation of the disc 503 so thatthe disc 503 rotates at the predetermined speed corresponding to the TVfield rate (3,600 rpm for NTSC signal) and at the predetermined phaserelationship relative to the vertical synchronization signal V_(D) ; andto make the servo lock signal SL high when the rotation of the disc 503substantially reaches the predetermined speed and phase relationship.

After the step S34, the control circuit 607 repeatedly checks the servolock signal SL from the motor control circuit 612 to ascertain whetherit has become high (step S35 in FIG. 26), and if the signal SL is foundto be high, the control circuit 607 then checks the second triggerswitch 621 to ascertain whether it has been closed by the depression ofthe trigger button 576 to the extent of the second step (step S36 inFIG. 26). If the switch 621 is found to be closed, the control circuit607 immediately activates the energization circuit 625 for apredetermined period of time (t), which is sufficient for releasing; andcauses the diaphragm control circuit 615 to hold the determined aperturesize (step S37 in FIG. 26). When triggered, the energization circuit 625energizes the coil 537a of the electromagnet 537 to weaken the magneticatractive force of the permanent magnets 537b and thus the armature 543is released. By this, the start lever 541 is rotated in the clockwisedirection by the spring 542 while causing, by its tail end part 541c,the latch lever 526 to rotate in the counterclockwise direction againstthe spring 527. Thus, the main drive lever 524 is unlatched and isrotated in the counterclockwise direction by the spring 525 whilehauling the mirror drive lever 528 against the spring 529 through thehaul lever 530. When the mirror drive lever 528 is rotated in thecounterclockwise direction, the view finder mirror 521 is rotated in theclockwise direction thorough the engagement of its pin 521a with the armpart 528a of the lever 528 and is retracted from the optical path. Atthe completion of the retraction of the mirror 521 from the opticalpath, the switch 564 is closed by the pin 521b of the mirror 521.Moreover, the pin 521a pushes the unlatch lever 534 at its projectedpart 534c and causes the same to rotate in the clockwise directionagainst the spring 535. Thus, the lever 534 causes, through its arm part534b, the latch lever 560 to rotate in the counterclockwise directionagainst the spring 561. Accordingly, the lever 561 releases the latchingof the cam 557 by its hook part 561a and the pressing of the contactpieces 563a to 563c of the switch 563 by the pin 560c. Thus, the contactpieces 563a to 563c of the switch revert to their normal, mutuallyseparated condition. This condition is shown in FIG. 24B.

After the step S37, the control circuit 607 repeatedly checks the switch564 to ascertain whether it is closed (step S38 in FIG. 26). If theswitch 564 is found to be closed, the control circuit 607 triggers theshutter control circuit 617 by making a trigger signal STR high insynchronism with the vertical synchronization signal V_(D) supplied bythe generation circuit 605 (step S39 in FIG. 26). When triggered, theshutter control circuit 617 immediately energizes the coil 618 of theelectromagnet to unlatch the first shutter blade 513. Thus, the firstblade 513 (FIG. 22) is pulled downwardly by the spring (not shown) toopen the aperture 512a. In this instance, the shutter control circuit617 simultaneously starts to count the exposure time set at the settingcircuit 616. When the count reaches the set exposure time, the controlcircuit 617 energizes the coil 619 of the electromagnet to unlatch thesecond shutter blade 514. Accordingly, the second blade 514 (FIG. 22) ispulled downwardly by the spring (not shown) to close the aperture 512a.Thus, the image pickup element 511 is exposed to the image light comingthrough the controlled diaphragm aperture for a period of exposure timeset at the setting circuit 616. The image signal generated in the pickupelement 511 in response to the exposure to the image light is read outand processed into the recording signal though the processing circuits601 and 602 in the next field period. Accordingly, the control circuit607 makes the gate circuit 603 turn on for one field period insynchronism with the next vertical synchronization signal V_(D) (stepS40 in FIG. 26) after the step S39. Thus, the recording signal issupplied to the head 505 through the gate circuit 603 and the amplifier604 and is recorded along a concentric track on the disc 503.

After the step S40, the control circuit 607 activates the motor drivecircuit 609 to drive the motor 551 (step S41 in FIG. 26). Thus, therotation shaft 554 is rotated together with the cams 555, 557 and 558 inthe clockwise direction through the gear train 552 and the gear 553. Atthis time, the projection 558a of the cam 558 causes the cam followerlever 562 to rotate in the clockwise direction as is shown in FIG. 24B.Thus, the lever 562 causes the return lever 532 to rotate in thecounterclockwise direction against the spring 533, which in turn causesthe haul lever 530 to rotate in the counterclockwise direction againstthe spring 531 to thereby release the hauling of the mirror drive lever528. Accordingly, the lever 528 is rotated in the clockwise direction bythe spring 529 and thus the mirror 521 returns to its original viewingposition in the optical path. By this, the unlatch lever 534 is freedfrom the pressure by the pin 521a of the mirror 521 and is rotated inthe counterclockwise direction by the spring 535. Thus, the latch lever560 is freed from the pressure by the unlatch lever 534 and is rotatedin the clockwise direction by the spring 561 so that the hook part 560aengages with the circumference of the cam 557. On the other hand, themain charge lever 556 is rotated in the clockwise direction against thespring 572 by the cam 555 through its pin 556b, which in turn rotatesthe charge lever 538 in the counterclockwise direction through the pin556c. Thus, the lever 538 rotates the drive lever 524 and the startlever 541 in the clockwise and the counterclockwise direction againstthe springs 525 and 542, respectively. At the final stage of itscounterclockwise rotation, the lever 524 is latched by the latch lever526 with the spring 525 being charged and the haul lever 530 comes toengage with the mirror drive lever 528. At this time, the arm part 524eof the lever 524 causes the arm members 515 and 517 to rotate in thecounterclockwise direction, respectively. Thus, the first and the secondshutter blades 513 and 514 are moved upwardly in FIG. 22. Moreover, thearmature 543 on the start lever 541 is atracted by the permanent magnets537b of the electromagnet 537. Further, the head 505 is shifted by onetrack pitch to the next recording position by the head shift mechanism611. When the cam 557 has made one revolution and the recess 557a comesto face the hook part 560a of the latch lever 560, the hook part 560aengages into the recess 557a and latches the cam 557. In this instance,the pin 560c of the lever 560 pushes the contact pieces 563a to 563c ofthe switch 663 to contact with each other. By the closure between thecontact pieces 563a and 563b, the motor drive circuit 609 short-circuitsthe motor 551. When short-circuited, the motor 551 immediately comes tostop and at the same time, generages an electrical voltage bycounterelectromotive effect. This voltage is supplied to the controlcircuit 607 through the connection between the contact pieces 563 and563c. On the other hand, the control circuit 607 repeatedly checks thevoltage level at this input connected to the contact piece 563c of theswitch to ascertain whether the switch 563 is closed (step S42 in FIG.26) after the step S41. If the voltage lever is found to be high due tothe closure of the switch 563, the control circuit 607 deactivates thecircuits 605, 609, 612 and 615 and thus the camera stops its operationafter the condition shown in FIG. 22 has been attained by the charging.

On the other hand, if the EVF unit and/or the NTSC adaptor unit areconnected by plugs to the sockets 501 and/or 502 respectively, thedetection pins 570 and /or 571 are moved in leftward in FIG. 22 andcause the mirror retracting lever 566 to rotate in the clockwisedirection against the spring 569. By this, the pin 567 on the lever 566causes the mirror drive lever 528 to rotate in the counterclockwisedirection against the spring 529 through its bent part 528c. Thus, themirror 521 is retracted from the optical path and the latch lever 560 iscaused to release the latching of the cam 557 by the unlatch lever 534in the same way, as explained hereinbefore. At this time, the switch 575is closed by the arm part 566c of the lever 566. Accordingly, thecontrol circuit 607 finds at the step S32 that the switch 575 is notopen. This means that the motion video mode has been designated. As aresult, the process goes to a step S44 in FIG. 26 where the controlcircuit 607 causes the switch circuit 624 to connect its output to itsinput terminal b (the output of the ALC circuit 623) and makes thecontrol signal CT high to cause the shutter control circuit 617 to beinsensitive to the output of the setting circuit 616. Then, the controlcircuit 607 activates the circuits 605 and 615 (step S45 in FIG. 26).Thus, the driving of the pickup element 511 by the drive circuit 606 isstarted. The control circuit 607 then triggers the shutter controlcircuit 617 by making the trigger signal STR high (step S46 in FIG. 26).In response thereto, the shutter control circuit 617 energizes the coil618 of the electromagnet for unlatching the first shutter blade 513.Thus, the first shutter blade 513 moves downwardly to open the aperture502a. On the other hand, the diaphragm control circuit 615 continuouslycontrols the aperture size of the diaphragm device based on the outputsignal of the ALC circuit 623 which produces the brightness signal inresponse to the luminous signal Y supplied by the image signalprocessing circuit 601. Thus, the camera operates in the motion videomode like a normal video camera; and at this time, the motion videosignal produced by the processing circuit 601 can be picked up throughthe sockets 501 and 502 by the EVF unit and the NTSC adaptor unit,respectively. This condition is maintained as long as the switch 620 iskept closed.

After the step S46, the control circuit 607 begins to repeatedly checkthe switch 620 to ascertain whether it has become open (step S47 in FIG.26). If the switch 620 is found to be open, the control circuit 607activates the energization circuit 625 for the predetermined period oftime (T)(step S48 in FIG. 26). Thus, the start lever 541 is released andthis in turn releases the latching of the main drive lever 524 by thelatch lever 526. Then, the control circuit 607 activates the motor drivecircuit 609 to drive the motor 551 (step S49 in FIG. 26). Thus, theshaft 554 is rotated in the clockwise direction and the main drive lever524 and the start lever 541 are reset by the cam 555 through the chargelevers 556 and 538. Moreover, the first shutter blade 513 is reset toclose the aperture 512a by the arm part 524e of the drive lever 524. Inthis case, however, the latch lever 560 is kept at the unlatchingposition shown in FIG. 248 by the pin 521a of the raised mirror 521through the unlatch lever 534. Therefore, the control circuit 607 checksthe switch 520 instead of the switch 563 to ascertain whether it hasbecome open (step S50 in FIG. 26) after step S49. If the switch 520 isfound to be open, this means that the resetting of the first shutterblade 513 to the closing position; and hence the charging of themechanism has been completed. Therefore, the control circuit 607deactivates the circuits 605, 609 and 615. Thus, the camera stops itsoperation. In this case, the cam 557 is stopped in a phase where itsrecess 557a substantially faces the hook part 560a of the latch lever560.

As will be appreciated from foregoing, in the present embodiment, it ispossible to set the still video recording camera in a motion video modeby a simple operation of connecting an external unit for the motionvideo pickup to the camera. Furthermore, the shutter is opened andclosed by the operation of the trigger switch and therefore, the imagepickup element and especially, its color filter are protected from beingdamaged by the direct impingement of high intensity light such as a sunlight. The opening and closing of the shutter in the motion video modemay be controlled by the operation of the power switch instead of thetrigger switch.

As will readily be appreciated from foregoing, with the presentinvention, the retraction and the resetting of the viewfinder opticalmeans relative to the optical path can be performed utilizing themovement of the output member of the prime mover means in the first andthe second direction, respectively and therefore, the mechanism foroperating the optical means and hence the camera mechanism can be madesimple and compact and reliable operation of the optical means isassured.

Furthermore, with the present invention, it becomes possible to utilizethe still video type camera as a usual motion video camera by adding asimple mechanical structure.

Furthermore, with the present invention, it becomes possible to set thestill video type camera in a motion video mode by a simple operation ofconnecting an external device to the socket means.

The present invention will not necessarily be limited to the abovementioned embodiments but many modifications and applications can bemade within the scope of the appended claims.

What is claimed is:
 1. A camera comprising:a first shutter membermovable between a rest position where it closes an aperture and a movedposition where it opens the aperture; a second shutter member movablebetween the rest position where it opens the aperture and a movedposition where it closes the aperture; latch means for latching saidfirst shutter member at its moved position; unlatch means responsive tomovement of said second shutter member to its moved position to releasesaid latch means; a viewfinder mirror; and means for moving said mirrorbetween a viewing position in an optical path and a retracted positionout of the optical path; said latch means being responsive to saidmoving means to latch said first shutter member at its moved positionwhen said mirror is moved to the retracted position by said movingmeans.
 2. A camera according to claim 1, further comprising:detectionmeans for detecting a scene brightness when the aperture is opened bythe movement of said first shutter member to its moved position; andshutter second means for causing said control and said first shuttermembers to be returned in the named order from their respective movedpositions to their respective rest positions with a time delay betweentheir respective return movements which corresponds to the scenebrightness detected by said detection means.
 3. A camera according toclaim 2, wherein said shutter control means is further arranged to causesaid first and said second shutter members to be moved in the namedorder from their respective rest positions to their respective movedpositions with a predetermined time delay between their respectivemovements.
 4. A camera according to claim 3, wherein said shuttercontrol means includes;first and second electromagnetic means arrangedto move said first and said second shutter member, respectively; andcircuit means for controlling said first and said second electromagneticmeans.
 5. A camera according to claim 4, further comprising:first andsecond urging members for urging said first and said second shuttermember toward their respective rest positions, respectively; and firstand second stopper members for stopping said first and said secondshutter member at their rest positions, respectively; said first andsaid second electromagnetic means being arranged to move said first andsaid second shutter members, respectively, to their respective movedpositions and to hold them against said first and said second urgingmembers, respectively.
 6. A camera according to claim 1, furthercomprising:a diaphragm device; and means for stopping down saiddiaphragm device; said latch means being responsive to said stop downmeans to latch said first shutter member at its moved position when saidstop down means stops down said diaphragm device.
 7. A camera accordingto claim 1, further comprising:means for operating said latch meansafter said first shutter member has been moved to its moved position. 8.A camera comprising:a first shutter member movable between a restposition where it closes an aperture and a moved position where it opensthe aperture; a second shutter member movable between a rest positionwhere it opens the aperture and a moved position where it closes theaperture; latch means arranged to latch said first shutter member at itsmoved position; unlatch means, including an electromagnet arranged torelease the latching of said first shutter member by said latch means; aviewfinder mirror; and means for moving said mirror between a viewingposition in an optical path and a retracted position out of the opticalpath; said latch means being responsive to said moving means to latchsaid first shutter member at its moved position when said mirror ismoved to the retracted position by said moving means.
 9. A cameraaccording to claim 8, further comprising:unlatch control means forcausing said unlatch means to release said latching when said secondshutter member is moved to its moved position, said unlatch controlmeans being connected to energize said electromagnet.
 10. A cameraaccording to claim 8, further comprising:detection means for detecting ascene brightness when the aperture is opened by the movement of saidfirst shutter member to its moved position; and shutter control meansfor causing said control and said first shutter member to be returned inthe named order from their respective moved positions to theirrespective rest positions with a time delay between their respectivereturn movements which corresponds to the scene brightness detected bysaid detection means.
 11. A camera according to claim 10, wherein saidshutter control means is further arranged to cause said first and saidsecond shutter members to be moved in the named order from theirrespective rest positions to their respective moved positions with apredetermined time delay between their respective movements.
 12. Acamera according to claim 11, wherein said shutter control meansincludes;first and second electromagnetic means for moving said firstand said second shutter members, respectively; and circuit means forcontrolling said first and said second electromagnetic means.
 13. Acamera according to claim 12, further comprising:first and second urgingmembers for urging said first and said second shutter members towardtheir respective rest positions, respectively; and first and secondstopper members for stopping said first and said second shutter membersat their rest positions, respectively; said first and said secondelectromagnetic means being arranged to move said first and said secondshutter members to their respective moved positions and to hold themagainst said first and second urging members, respectively.
 14. A cameraaccording to claim 8, further comprising:a diaphragm device; and meansfor stopping down said diaphragm device; said latch means beingresponsive to said stop down means to latch said first shutter member atits moved position when said stop down means stops down said diaphragmdevice.
 15. A camera according to claim 8, further comprising:means foroperating said latch means after said first shutter member has beenmoved to its moved position.
 16. A camera comprising:a first shuttermember movable between a rest position where it closes an aperture and amoved position where it opens the aperture; a second shutter membermovable between a rest position where it opens the aperture and a movedposition where it closes the aperture; latch means for latching saidfirst shutter member at its moved position; and trigger means includingan electromagnet to cause said latch means to latch said first shuttermember; unlatch means responsive to movement of said second shuttermember to its moved position to release the latching of said firstshutter member; a viewfinder mirror; and means for moving said mirrorbetween a viewing position in an optical path and a retracted positionout of the optical path; said latch means being responsive to saidmoving means to latch said first shutter member at its moved positionwhen said mirror is moved to the retracted position by said movingmeans.
 17. A camera according to claim 16, further comprising:detectionmeans for detecting a scene brightness when the aperture is opened bythe movement of said first shutter member to its moved position; andshutter control means for causing said second and said first shuttermember to be returned in the named order from their respective moved totheir respective rest positions with a time delay between theirrespective return movements which corresponds to the scene brightnessdetected by said detection means.
 18. A camera according to claim 17,wherein said shutter control means is further arranged to cause saidfirst and second shutter members to be moved in the named order fromtheir respective rest to their respective moved positions with apredetermined time delay between their respective movements.
 19. Acamera according to claim 18, wherein said shutter control meansincludes;first and second electromagnetic means for moving said firstand second shutter members, respectively; and circuit means forcontrolling said first and said second electromagnetic means.
 20. Acamera according to claim 19, further comprising:first and second urgingmembers for urging said first and said second shutter members towardtheir respective rest positions, respectively; and first and secondstopper members for stopping said first and said second shutter membersat their rest positions, respectively; said first and secondelectromagnetic means being arranged to move said first and said secondshutter members to their respective moved positions and to hold themagainst said first and second urging members, respectively
 21. A cameraaccording to claim 16, further comprising:trigger control means foroperating said trigger means after said first shutter member has beenmoved to its moved position, said trigger control means being connectedto said electromagnet.